Futaba S-bus usage with 8ch rec.

I am using a 8channel receiver with the T14SG transmitter. I would like to use 9 channels and since the transmitter setup shows 14 channels available it seems the submode could be assigned the ch9 and the flaps and trap door connected directly to the receiver. However the transmitter setup automatically assigns the submode to channel 7, gain being on channel 6. So that leaves flaps connected to ch8 on the receiver. I can't seemed to get access to the other 6 channels. Do I need an S-Bus servo connected say to channel 6 or 7? Don't want to by one if not needed.

I am using a 8channel receiver with the T14SG transmitter. I would like to use 9 channels and since the transmitter setup shows 14 channels available it seems the submode could be assigned the ch9 and the flaps and trap door connected directly to the receiver. However the transmitter setup automatically assigns the submode to channel 7, gain being on channel 6. So that leaves flaps connected to ch8 on the receiver. I can't seemed to get access to the other 6 channels. Do I need an S-Bus servo connected say to channel 6 or 7? Don't want to by one if not needed.

When you have the 14SG set to output 8 channels (S-FHSS) it will only output 8 channels even though you can see 14 channels in the transmitter setup.
Page 73 of the Futaba manual.

To use more channels you need to set the Tx to output 12ch (FASSTest 14CH, FASSTest 12CH, FASST MULTI) but then you need to use an appropriate receiver, example R6208SB.
With this receiver you can have 12 channels going to the Vector (I'm assuming), and you have access to 8 PWM outputs to do your flaps , head tracking or trap door etc.

Assign these functions to the higher channels (9 - 16) in your tx and set your receiver to output those channels on the physical pins of the receiver.

I have both a R2008SB and a R7008SB neither can be used with analog servos which I'm sure the Bushmule uses. Don't know that for sure since no user manual is available.
Thanks for the reply. At least I understand a bit more now